Interpretive Summary: Improving the ability of cotton to protect itself against insect pests (Host Plant Resistance) has long been a goal of plant breeders. Despite the fact that improvements have been made by a number of researchers over the past 50 years, chemical control of insect pests has remained the preferred method for most production systems. The introduction of Bt cotton and the pressure to decrease insecticide use has renewed interest in increasing the plant's endogenous defenses against insect pests. A number of simply inherited traits have been identified that can improve the plant's defenses against various insect pests. Each individual trait is not enough to provide adequate protection, but in combination, should provide a defense network that could further reduce insecticide usage. A strategy has been designed to incorporate these traits into a single cotton variety in order to increase the plant's defense against various pests. The parents chosen for combining the traits not only have the trait of interest, but also have good fiber properties and lint yield, thereby eliminating the need for extensive backcrossing and selection to recover a line with acceptable agronomic characteristics. If the Bt gene can be incorporated into these new breeding lines, Host Plant Resistance can be further improved.

Technical Abstract:
Improved Host Plant Resistance (HPR) has long been a goal of plant breeders. Despite the fact that improvements have been made by a number of researchers over the past 50 years, chemical control of insect pests has remained the preferred method for most production systems. The introduction of Bt cotton and the pressure to decrease insecticide use has renewed interest in increasing the plant's endogenous defenses against insect pests. A number of simply inherited traits have been identified that can improve the plant's defenses against various insect pests. Each individual trait is not enough to provide adequate protection, but in combination, should provide a defense network that could further reduce insecticide usage. The traits being combined include semi-smooth leaf which deters some insects from feeding and inhibits egg laying, nectariless which eliminates nectaries that can be an insect attractant, high glanding which produces glands on the calyx crown and decreases bud/bollworm feeding and semi-glanded which decreases the number of glands in seed, but has near normal glanding on other plant parts. The parents chosen for combining the traits not only have the trait of interest, but also have good fiber properties and lint yield, thereby eliminating the need for extensive backcrossing to recover a line with acceptable agronomic characteristics. If the Bt gene is incorporated into these new breeding lines, Host Plant Resistance can be further improved.